Active matter

Blinks used a different method to dislodge the particles of active material from the strips cut off from the jellyfish (Blinks et al., 1978). The strips are shaken in cold seawater, and the particles dislodged are harvested by filtration on a Buchner funnel with the aid of Celite. The filter cake is first washed with 50 mM EDTA, pH 8.0, containing (NH4)2S(>4 at 75% saturation, to remove seawater. Then, the particles are cytolyzed and aequorin is extracted in situ by washing the filter cake with cold 50 mM EDTA, pH 8.0. The filtrate is clear and slightly greenish. The active matter in the filtrate is precipitated by saturation... 

TABLE 3 Hoechst Sulfoxidation Energy Consumption (per 100 kg active matter)... 

The alkanesulfonate melt is treated with 4 bar of water to give a paste containing 60% active matter (12) or pelletized by means of a cooling conveyor with a special feeding device (not shown in Fig. 2). The solid product is composed of 93 wt % of alkanesulfonate, 6 of sodium sulfate, and 1 of paraffin. 

The energy consumption per 100 kg active matter is shown in Table 3. In Table 4 an example is given for the specifications of a commercial product [5]. 

The byproduct is a stoichiometric amount of 60 wt % H2S04, which is used in the chemical industry. The wastewater (0.3 m3/100 kg active matter), which contains paraffin, oxidation products of the paraffin, alkanesulfonate, and sulfur dioxide, has a chemical oxygen demand (COD) of 1800 mg/L and is readily biodegradable (>95% after 7 days). The sulfur dioxide emission after repeated washing of the off-gas amounts to 0.5 g/100 kg active matter [6]. 

The energy consumption per 100 kg sodium paraffin sulfonates (100% active matter) is given in Table 7. 

The rheology and phase behavior of sodium linear C16-C18 alcohol sulfate and sodium oxo C14-Cl5 (80% linear) alcohol sulfate was studied by van Zon et al. [75]. The oxoalcohol sulfate can be prepared as a handleable 65-70% concentrate. The linear C16-C18 alcohol sulfate only allows 55-60% as maximum concentration. The hexagonal phase of the oxoalcohol sulfate extends from 38% to 55% active matter whereas the hexagonal band of the linear alcohol sulfate is very narrow, only extending from 35% to 40% and its crystallization line is situated at a higher level than for the oxo derivative. 

FIG. 15 Foaming capacity of alcohol sulfates and alcohol ether sulfates at 0.28 g/L active matter at 20°C, DIN 53902. (From data in Ref. 149.)... 

Sodium dodecyl sulfate is the universal analytical standard for the determination of anionic and cationic active matter. It is used to determine the analytical concentration factor of the cationic surfactant in the titration of anionic active matter and as titrant to determine the cationic active matter. 

An analysis of alcohol and alcohol ether sulfates should determine the anionic active matter, the unsulfated matter, the inorganic sulfate content, the chloride content, and water. Other more precise analysis must determine the alkyl chain distribution of the alcohol and in the case of alcohol ether sulfates the number of ethoxy groups and its distribution, as well as other more specialized determinations, such as the content of 1,4-dioxane and other impurities. 

The complete analysis of alcohol sulfates is described in the Standard Methods of the International Organization of Standards (ISO) [200] and of the American Society for Testing and Materials (ASTM) [201]. These methods describe the analysis of inorganic sulfate content, chloride content, unsulfated matter, and water as well as other analytical values. Other ISO standards describe the analysis of sodium secondary alkyl sulfates [202], determination of pH [203], determination of water content [204,205], chlorides [206], total active matter in sul fated ethoxylated alcohols and alkylphenols [207], mean relative molecular mass in sulfated ethoxylated alcohols and alkylphenols [208], sulfate content... 

The method developed by Epton [212,213] became the universally accepted method for the analysis of active matter of anionic and cationic surfactants. Epton s method, also known as the two-phase titration, is based on the titration of the anionic surfactant with cetylpyridinium bromide, a cationic surfactant, in the presence of methylene blue as indicator. A solution of the anionic surfactant is mixed with the indicator dissolved in dilute sulfuric acid, followed by further addition of chloroform, and then it is titrated with the cationic surfactant. Methylene blue forms a complex with the anionic salt that is soluble in chloroform, giving the layer a blue color. As the titration proceeds there is a slow transference of color to the water layer until the equivalence point. At the equivalence point colors of the chloroform and water layers are visually the same. On successive additions of titrant the chloroform layer lightens in shade and finally becomes colorless. 

ISO 6842 1989, Surface active agents Sulfated ethoxylated alcohols and alkyl-phenols—Determination of total active matter content. 

ISO 2271 1989, Surface active agents Determination of anionic-active matter by manual or mechanical direct two-phase titration procedure. 

According to [4], IOS consists typically of sodium (3-hydroxysulfonate (85%), sodium alkenesulfonate (10%), sodium y/5-hydroxysulfonates (5%), and residual sultones (usually less than 6 ppmw on active matter). IOS too can be regarded as a surfactant system in the sense referred to above. 

The inherent lability of alkene- and hydroxyalkanesulfonates, variations in isomer composition, and the presence of the disulfonates are features which complicate AOS analyses. Improper sample handling, such as exposure to high temperatures, can also alter active matter composition. Consequently, analytical procedures have been developed that minimize potential sources of error. 

The types of analyses discussed in this section can be divided into two groups active matter and impurities. Several methods assess the anionic surfactant (active matter) content of the AOS product. These are particularly important since detergent performance is directly related to surfactant concentration. The different types of anionic active material are identified and quantified. 

Active matter (anionic surfactant) in AOS consists of alkene- and hydroxy-alkanemonosulfonates, as well as small amounts of disulfonates. Active matter (AM) content is usually expressed as milliequivalents per 100 grams, or as weight percent. Three methods are available for the determination of AM in AOS calculation by difference, the two-phase titration such as methylene blue-active substances (MBAS) and by potentiometric titration with cationic. The calculation method has a number of inherent error factors. The two-phase titration methods may not be completely quantitative and can yield values differing by several percent from those obtained from the total sulfur content. These methods employ trichloromethane, the effects from which the analyst must be protected. The best method for routine use is probably the potentiometric titration method but this requires the availability of more expensive equipment. 

The value obtained for active matter by this method can be used to calculate average equivalent weight of the sample. 

The amount of residual sulfonate ester remaining after hydrolysis can be determined by a procedure proposed by Martinsson and Nilsson [129], similar to that used to determine total residual saponifiables in neutral oils. Neutrals, including alkanes, alkenes, secondary alcohols, and sultones, as well as the sulfonate esters in the AOS, are isolated by extraction from an aqueous alcoholic solution with petroleum ether. The sulfonate esters are separated from the sultones by chromatography on a silica gel column. Each eluent fraction is subjected to saponification and measured as active matter by MBAS determination measuring the extinction of the trichloromethane solution at 642 nra. (a) Sultones. Connor et al. [130] first reported, in 1975, a very small amount of skin sensitizer, l-unsaturated-l,3-sultone, and 2-chloroalkane-l,3-sultone in the anionic surfactant produced by the sulfation of ethoxylated fatty alcohol. These compounds can also be found in some AOS products consequently, methods of detection are essential. 

One-dimensional thin-layer chromatography. This method, based on the work of Wolf and McPherson, will determine more than 0.1% terminal 8-sultones in the neutral oil. This implies that if the AOS contains 1% neutral oil, greater than 30 ppm (active matter basis) of terminal 5-sultones can be determined. Some samples contain a compound having an R( of approximately 0.03 U less than the 5-sultones. This should not be reported as terminal 8-sultones. C14 and C16 terminal 8-sultones have the same retention (R 0.35-0.55, depending on the humidity) and therefore appear as one spot. 

Methods of analysis for the determination of active matter and minor impurities in AOS are described in ASTM D3673-89. Included are methods for determination of moisture, sulfate, chloride, alkalinity, pH, color, and neutral oil. Some alternative instrumental methods are described briefly below. 

Alkalinity measurement is also required for the determination of active matter by difference and equivalent weight calculations. It can be determined as two of the following compounds sodium bicarbonate, sodium carbonate, or sodium hydroxide. The sample is titrated to a phenolphthalein endpoint to determine the sodium hydroxide/sodium carbonate content. An added measure of acid converts any bicarbonate to carbon dioxide, which is subsequently removed from the solution. Back-titration of the excess acid gives a measure of the amount of bicarbonate and/or carbonate present. 

Neither the reaction to the intermediate maleic acid monoester nor the subsequent sulfation to the sulfosuccinic acid monoester sodium salt is fully complete (Scheme 2). Around 80% of the solid material is estimated to be true sulfosuccinate. Whether the unreacted material or possible side products are beneficial to the finished product has not yet been evaluated. Due to the necessity of dissolving the sodium sulfite (or bisulfite) in water, the product obtained is not normally more highly concentrated than 40% active matter. The consistency of the material varies from clear, low viscous liquids to pastes. Some substance can be spray-dried to obtain concentrated powders. 

The hydrolytic behavior of sulfosuccinates as such and in formulations is depicted in the following pictures (Figs. 4-7). Two substances-DLAS and DLSS—were chosen to illustrate these properties. The tests were performed at room temperature and 40°C at various pH values (pH = 5, 6, 8) and—in the case of DLSS—without adjusting pH in a long-term run (24 weeks). Changes were evaluated by determination of pH and active matter. 

---